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Structure: Structure of the Heart

The heart is a hollow muscular pump consisting mainly of myocardium, a type of muscle that can work without resting. The interior of the heart is divided into two halves, each of which consists of an upper chamber and a lower chamber (the atrium and the ventricle). Each chamber connects to one or more blood vessels. Blood flow through these chambers is controlled by one-way valves.

Location

Anchoring the valves

String-like chordae tendineae anchor each valve cusp (flap) to the heart wall to prevent it from being turned inside out.

Heart muscle

The numerous mitochondria (energy-producing units) in heart muscle cells enable the heart to pump without resting.

Function: Blood supply to the heart

The coronary arteries branch off the aorta and surround and penetrate heart muscle. Arterioles and capillaries branch off from the arteries to supply heart muscle with oxygen-rich blood. Deoxygenated blood drains into the coronary veins, which carry it back into the heart’s right atrium.

The coronary arteries

There are two main coronary arteries, the left and the right. The left one branches to form the left circumflex artery and the left anterior descending artery.